In livestock farming, diarrhea of domestic animals and poultry has been a serious problem. For example, diarrhea and other digestive diseases that occur in cattle in the nursing and growth periods pose critical problems, the problems including not only death due to the diseases but also physical exhaustion and significant influence upon the normal growth of internal organs [Kazunori Hashimoto, The Beef Cattle Magazine, Vol. 5, No. 11, p. 38 (1988)]. In fact, in raising beef cattle, the incidence of digestive diseases with diarrhea as the major symptom in the nursing period is 13.3% [Toshio Nakane, Animal Husbandry, Vol. 33, No. 1, p. 37 (1979)]. Also, the rate of death and culling of dairy cows during the nursing and growth periods is 11.9%, the major causes being diarrhea and pneumonia [Hiroyuki Tojyo et al., Animal Husbandry, Vol. 40, No. 1, p. 51 (1986)]. Concerning adult cattle, diarrhea decreases feed efficiency, even if not lethal, resulting in decreased milk yield, milk quality and meat quality, which means considerable commercial loss.
The same applies to pigs and pet animals. It is common practice of breeding husbandry of these animals to grow babies apart from their dams from just after parturition. Such neonates are very low in antigenicity, easily permit pathogen growth because of the absence of intestinal bacterial flora, and are susceptible to various stresses. These factors interact with each other, causing diarrhea, which results in very high mortality and, if not lethal, significantly affects growth thereafter and causes poor development.
The same also applies to fowls. Diarrheal chicks are generally poor in development, showing body weight loss and increased body weight variation; these factors adversely affect productivity thereafter, resulting in decreased proportions of sale for production in broilers and decreased egg laying rates in egg laying hens. It is also known that antibody production capability after vaccination decreases.
Such diarrhea is caused by very complex factors. In addition to infectious diarrhea caused by toxins produced by pathogenic bacteria and diarrheal viruses, such as Clostridium perfringens type A, Clostridium perfringens type C, Salmonella typhimurium, Salmonella dublin, Campylobacter jejuni, Campylobacter coli, Escherichia coli 0-88, Escherichia coli 0-99, Escherichia coli 987P, Staphylococcus aureus, Rotavirus KK-3 and Rotavirus NCDV, or caused by intestinal bacterial floral changes due to infection with these bacteria and viruses, high incidence is reported of noninfectious diarrhea, e.g., diarrhea of unknown cause not associated with infectious microorganisms, such as stress diarrhea, which occurs due to stresses on domestic animals, poultry and pet animals.
These stresses on domestic animals, poultry and pet animals are known to be caused by three factors: environmental, nutritive and psychological changes. Specifically, there are various stress-causing factors, including over-crowding, lack of exercise, inappropriate livestock house sanitation due to lack of labor, feed composition changes due to parturition, and long-distance transportation during the weaning period.
In addition, it is appropriate to allow neonates to grow under protection by dams for a given period of time. For improving productivity or economy in livestock farming, however, it is now common practice of breeding husbandry to raise neonates apart from their dams from just after parturition, except for beef cattle. Most neonates isolated from their dams are gathered at nursing facilities etc. about 1 week after parturition, and grown collectively. In such period, neonates soon after birth are very low in antigenicity, easily permit pathogen growth because of the absence of intestinal bacterial flora, and are susceptible to various stresses. It is speculated that these factors interact with each other and easily cause diarrhea.
Traditionally, infectious diarrhea has been effectively prevented or treated by administering antibiotics to domestic animals, poultry and pet animals. However, this method is subject to limitation as to the kind and quantity of safely usable antibiotics, and has become doubtful as to efficacy in view of the occurrence of resistant bacteria ants safety. As a substitute for this method, various naturally-occurring antimicrobial substances have been used; for example, tea extract is shown to exhibit activity against infectious microorganisms or viruses (Japanese Patent Laid-Open Nos. 1-265023 and 2-276562). However, when tea extract is used alone or in combination with feed for infectious diarrhea, its effect is weak and doubtful for practical use. Also, when a specific antibody is used alone, because of the specificities of various kinds of pathogenic microorganisms, only therapeutic effect is obtained, with no preventive effect against diarrhea, so that the efficacy is not sufficient for practical use.
On the other hand, for preventing and treating noninfectious diarrhea, neonates are fed with sufficient colostrum from after parturition. Also, since stress on animals causes intestinal bacterial floral changes, such as increased susceptibility to infectious microorganisms, methods similar to those used for infectious diarrhea, or various probiotics or oligosaccharides are used. However, these methods are nothing more than nosotropic therapies. Also, probiotics and oligosaccharides have problems as to duration of efficacy. As for stress prevention, pigs are allowed to freely bite iron chains or old tires suspended in their pigsty or bedding straws placed in their pigsty daily to relieve pigs' boredom. However, these are passive prevention methods, and can apply to limited kinds of domestic animals, poultry and pet animals. Japanese Patent Examined Publication No. 3-17469 discloses a domestic animal acclimation composition for relieving stress, but it does not intend to suppress noninfectious diarrhea. The same applies to the method disclosed in Japanese Patent Examined Publication No. 3-70458, and that method is limited by rearing time and environment. In this situation, there is so far no feed additives or animal feeds containing them that effectively suppress the occurrence of noninfectious diarrhea in domestic animals, poultry and pet animals.
Also, the fresh milk produced by domestic animals is traded with ranking in terms of milk fat percentage, solids-not-fat percentage, cell count and milk protein percentage. For example, fresh milk of rank A is required to have a milk fat percentage of not less than 3.5%, a solid-not-fat percentage of not less than 8.5%, a cell count of not more than 300,000 and a milk protein percentage-of not less than 3.0%. Fresh milk outside these ranges cannot be traded in usual way, and fresh milk that fails to meet all these requirements should pay penalty. In other words, fresh milk qualified as rank A must has a certain levels of milk fat percentage, solid-not-fat percentage, cell count, and milk protein percentage. For these reasons, milk quality declining results in considerable economic loss for dairy farmers. Similarly, milk yield reduction leads to economic loss due to decreased productivity.
In this situation, there have been various attempts of improvement, which are mainly concerned with concentrates, to improve milk quality and increase milk yield (Japanese Patent Laid-Open Nos. 2-145154 and 2-286047).
However, countermeasures based on the above-described approach do not provide sufficient effect; there is need far measures for further improvement.
As for reproductive efficiency, when the quantity of milk produced by dairy cows is increased, inappropriate breeding husbandry can immediately cause infertility. This can cause infertility in a large number of cattle in a short period of time. However, there is now absolutely no therapeutic or prophylactic method effective against infertility [Toshihiko Nakao, Animal Husbandry, Vol. 44, No. 10, pp. 1143-1149 (1990)].
Domestic animals, such as dairy cows, beef cattle, pigs, and fowls, have recently been increasingly utilized, with a tendency to use concentrates, as described above, for improving productivity to increase economic efficiency. However, in comparison with conventional raw material type feed, concentrates give greater burden on the gastrointestinal organs, posing various problems, including decreased growth rate, decreased milk yield, and deterioration of meat quality in domestic animals.
Also, intensified breeding has increased the incidence of bacterial or viral diarrhea due to various factors, such as stress, as stated above; this situation poses industrially significant problems, including hampering of livestock house maintenance. Moreover, administration of antibiotics and potent antimicrobial agents against disease pose many problems, including disturbance of the digestive organs and intestinal bacterial flora in domestic animals, which can induce new disease. Another problem is anxiety regarding commercial value reduction and safety, due to persistence of these chemicals in milk and food meat.
On the other hand, fecal and urinary malodor generated from livestock houses significantly affect the environment. Diarrheal feces, in particular, are extremely malodorous, posing significant problems, such as malodor pollution. However, there is no effective solution to the improvement of such breeding environments.